The present invention concerns a method for the production of stanol fatty acid esters, a stanol fatty acid ester composition, and the use thereof in food products, in particular in fat based food products in amounts sufficient to obtain a blood cholesterol lowering effect if the food product is used according to the common needs of the consumer.
Fatty acid esters of phytosterols and/or phytostanols are hydrolysed in the gut and the subsequent free phytosterols and/or phytostanols will inhibit the absorption of cholesterol thereby lowering the blood cholesterol. Free phytosterols and/or phytostanols themselves are hardly absorbed. Indications in literature are that phytostanols are absorbed even in a lesser extend than phytosterols. The use of phytostanols in fat based food products to lower blood cholesterol could therefore be preferred over the use of phytosterols.
In U.S. Pat. No. 5,502,045 (Raision Tehtaat Oy AB) a substance of beta-sitostanol fatty acid ester is described produced by 1. solvent hardening of beta-sitosterol followed by 2. esterification of the formed beta-sitostanol with fatty acids. The so formed mixture of beta-sitostanol fatty acid esters can be used as such or added to a food.
There are several disadvantages to this production method, of which the most severe is that the beta-sitosterol should first be solubilized in a solvent (e.g. ethylacetate, butanol, ethanol) before the hardening of the sterol can be performed. Because the solubility of beta-sitosterol, or phytosterols in general, in solvents is rather limited, the hardening step is a relatively expensive operation because of high solvent costs and high costs of hardening equipment of relatively large volume. Moreover, the solvents need to be recovered after the hardening process is completed, and suitable locations for above hardening process will be limited because of environmental regulations. Furthermore, in a process aiming at the production of a food ingredient, removal of all solvents is essential, this making the process even more expensive.
It has been observed that the stability of fat based food products diminishes by the addition of sterols and stanols thereto, in particular when the sterols/stanols are used at higher levels. As sterols and stanols are not very soluble in fat large crystals thereof are found in the products prepared with these sterols or stanols. For example, very serious crystal formation is observed at 3-4% sterol levels On the other hand, however, the use of these higher levels is often required to obtain the significant cholesterol reduction level that is desired.
It is well known that by esterification of sterols/stanols with fatty acids, the solubility can be increased. However, a disadvantage of esterification is that this decreases the efficacy of the sterol/stanol compounds to lower the blood cholesterol level. Another disadvantage found in the use of sterol/stanol fatty acid esters is that the absorption of lipophilic micronutrients (like beta-carotene) decreases (Gyling HK et al (1996) Circulation 6: I-578).
Another disadvantage found with the esterification of sterols/stanols is found in the production thereof, requiring long processing times and/or high processing costs.